Phys.org
Hawking radiation
The faint glow that means black holes are not quite black, and eventually evaporate.
Stephen Hawking showed in 1974 that quantum effects at the horizon cause a black hole to radiate with a temperature inversely proportional to its mass. For any astrophysical black hole the temperature is far below the cosmic microwave background, so they gain more than they lose and the evaporation is entirely theoretical for now. The result matters anyway: it is the one place where gravity, quantum mechanics and thermodynamics all have to agree, and the information paradox it created is still unresolved.
Where it has come up lately
Related terms
Event horizon
The boundary around a black hole past which nothing gets out — not a surface, but a point of no return.
Accretion disc
The flat, ferociously hot spiral of matter falling onto a compact object.
Singularity
The point where our description of gravity stops producing meaningful answers.
Schwarzschild radius
How small you would have to squeeze something to make it a black hole.
Questions
What is Hawking radiation?
The faint glow that means black holes are not quite black, and eventually evaporate.
Why does it matter?
For any astrophysical black hole the temperature is far below the cosmic microwave background, so they gain more than they lose and the evaporation is entirely theoretical for now. The result matters anyway: it is the one place where gravity, quantum mechanics and thermodynamics all have to agree, and the information paradox it created is still unresolved.